We can take pride in the fact that there is no science as certain as ours [alchemy] because it teaches by experience which is the mother, the source and the universal cause of all knowledge: and it is for the lack of this that Aristotle and the other philosophers have wondrously failed in their philosophy.

In: Allen G. Debus - The French Paracelsians - Chapter 3 (p. 72), Cambridge University Press. 1991